1. Field of the Invention
The present invention relates to a communication apparatus and a method for controlling use of a service.
2. Description of the Related Art
In recent years, a home network system including home electric appliances such as a digital television, a hard disk recorder, and a personal computer (PC) can process multimedia data. In the home network, these appliances are connected, for example, via a wireless local area network (LAN) or a wired local area network (wired LAN). A protocol standardized by Digital Living Network Alliance (DLNA) is used for sending and receiving data over the LAN.
On the other hand, a technology, which establishes a virtual communication path (session) between communication apparatuses to communicate to each other over an Internet protocol (IP) network, has been becoming widely used (see Japanese Patent Application Laid-Open No. 2005-33528).
As a session control protocol for controlling the establishment, the continuation, and the disconnection of a session between communication apparatuses, Session Initiation Protocol (SIP) in the Request for Comments (RFC) 3261 is used. Its specification is published by Internet Engineering Task Force (IETF).
When a service has been performed using apparatuses located on different networks, such a case may occur that a service in one network ends while a service in the other network does not.
A service will be described, for example, which is performed between a digital television having a digital media server (DMS) function and a storage server having a digital media player (DMP) function, both of which are standardized by DLNA, after the session therebetween is established. In addition, the DMP is a client that reproduces content data. The DMS is a server that supplies content data.
In this case, if the data supply by the storage server, located on a different network from the digital television, ends while the digital television is receiving data and reproducing the received data, the digital television on the network may issue a data request for the disconnected service.
Furthermore, in this case, a session may not be disconnected or the data supply by a storage server on another network may not end even when the digital television has ended the service for receiving data and reproducing the received data during the session.